| Android | 54+ MB |
| Linux | 32-bit | Modern | Open-source | C++ | CD | Android x86 1.6-r2 |
| Arch Linux | 15+ MB |
| Linux | 32-bit | Modern | Open-source | C | 9pfs | Various packages, including Xorg, Firefox and more |
| Buildroot Linux | 4.9 MB |
| Linux | 32-bit | Modern | Open-source | C | bzImage | Minimal Linux with Lua, ping, curl, telnet |
| Damn Small Linux | 50 MB |
| Linux | 32-bit | Historic | Open-source | C | CD | 4.11.rc2 with Firefox 2.0 |
| ELKS | 1.2 MB |
| Linux-like | 16-bit | Modern | Open-source | C | HD | Linux for 8086 |
| NodeOS | 14 MB |
| Linux | 32-bit | Modern | Open-source | C | bzImage | Linux with nodejs as /bin/init |
| Tilck | 16 MB |
| Linux-like | 32-bit | Modern | Open-source | C | HD | Tiny Linux-Compatible Kernel |
| FreeBSD | 16+ MB |
| BSD | 32-bit | Modern | Open-source | C | HD | FreeBSD 12.0 |
| NetBSD | 23+ MB |
| BSD | 32-bit | Modern | Open-source | C | HD | NetBSD 4.0 with Xorg |
| OpenBSD | 11+ MB |
| BSD | 32-bit | Modern | Open-source | C | HD | OpenBSD 6.6 |
| FiwixOS | 4.2+ MB |
| Unix-like | 32-bit | Modern | Open-source | C | HD | With Doom |
| Minix | 30+ MB |
| Unix-like | 32-bit | Modern | Open-source | C | CD | Minix 3.3 |
| Redox | 31+ MB |
| Unix-like | 32-bit | Modern | Open-source | Rust | HD | A Unix-like microkernel OS written in Rust |
| SerenityOS | 16+ MB |
| Unix-like | 32-bit | Modern | Open-source | C++ | HD | Web browser, various games and demos |
| Sortix | 67 MB |
| Unix-like | 32-bit | Modern | Open-source | C++ | CD | A small self-hosting Unix-like operating system |
| Soso | 7.6 MB |
| Unix-like | 32-bit | Modern | Open-source | C | CD | A Simple Unix-like operating system |
| Syllable | 28+ MB |
| Unix-like | 32-bit | Historic | Open-source | C++ | HD | A user friendly, POSIX compatible OS |
| Unix V7 | 0.5+ MB |
| Unix | 32-bit | Historic | Proprietary | C | HD | |
| BeOS 5 | 34+ MB |
| BeOS | 32-bit | Historic | Proprietary | C++ | HD | With Opera 3.62, NetPositive |
| Haiku | 41+ MB |
| BeOS | 32-bit | Modern | Open-source | C++ | HD | Networking (WebPositive), OCaml, 2048, NetHack |
| AROS Broadway | 25+ MB |
| AmigaOS | 32-bit | Modern | Open-source | C | CD | AmigaOS-like graphical OS |
| Icaros Desktop | 60+ MB |
| AmigaOS | 32-bit | Modern | Open-source | C | CD | AmigaOS-like graphical OS |
| Tiny Aros | 17+ MB |
| AmigaOS | 32-bit | Modern | Open-source | C | CD | AmigaOS-like graphical OS |
| 9front | 4.9+ MB |
| Plan 9 | 32-bit | Modern | Open-source | C | HD | An actively maintained fork of Plan 9 |
| ReactOS | 17+ MB |
| Windows-like | 32-bit | Modern | Open-source | C++ | HD | QtWeb, LBreakout2, OpenTTD, Bochs, TCC |
| Windows 1.01 | 0.7 MB |
| Windows | 16-bit | Historic | Proprietary | ASM, C | Floppy | Reversi, Paint |
| Windows 2.03 | 1.8 MB |
| Windows | 16-bit | Historic | Proprietary | ASM, C | HD | Reversi, Paint |
| Windows 3.0 | 6.5 MB |
| Windows | 16-bit | Historic | Proprietary | ASM, C | CD | |
| Windows 3.1 | 17 MB |
| Windows | 16-bit | Historic | Proprietary | ASM, C | HD | QBasic, Minesweeper, Solitaire |
| Windows 95 | 19+ MB |
| Windows | 32-bit | Historic | Proprietary | ASM, C | HD | Age of Empires, FASM, POV-Ray, Hover! |
| Windows 98 | 11+ MB |
| Windows | 32-bit | Historic | Proprietary | ASM, C | HD | FreeCell, Hearts, sheep.exe, IE 5 |
| Windows ME | 14+ MB |
| Windows | 32-bit | Historic | Proprietary | ASM, C | HD | Visual Basic, Office 97 |
| Windows NT 3.1 | 18+ MB |
| Windows | 32-bit | Historic | Proprietary | C++ | HD | |
| Windows NT 3.51 | 28+ MB |
| Windows | 32-bit | Historic | Proprietary | C++ | HD | Internet Explorer 3 and Visual FoxPro 3.0 |
| Windows NT 4.0 | 16+ MB |
| Windows | 32-bit | Historic | Proprietary | C++ | HD | |
| Windows 2000 | 21+ MB |
| Windows | 32-bit | Historic | Proprietary | C++ | HD | IE 6, K-Meleon, Winamp, Delphi, NetHack and more |
| 86-DOS | 0.1 MB |
| DOS | 16-bit | Historic | Proprietary | ASM | Floppy | |
| Exploring IBM | 0.1 MB |
| DOS | 16-bit | Historic | Proprietary | ASM | Floppy | |
| FreeDOS | 0.6 MB |
| DOS | 16-bit | Modern | Open-source | ASM, C | Floppy | nasm, vim, debug.com, Rogue, various demos |
| FreeGEM | 1.6+ MB |
| DOS | 16-bit | Historic | Open-source | ASM, C | HD | Graphical desktop for FreeDOS |
| Xcom | 1.3 MB |
| DOS | 16-bit | Historic | Open-source | ASM, C | Floppy | Graphical desktop for FreeDOS |
| MS-DOS 4 | 0.5 MB |
| DOS | 16-bit | Historic | Proprietary | ASM | Floppy | |
| MS-DOS 6.22 | 2.4+ MB |
| DOS | 16-bit | Historic | Proprietary | ASM | HD | Doom, Sim City, OCaml 1.0, Turbo C and more |
| PC-MOS/386 | 0.7 MB |
| DOS | 32-bit | Historic | Proprietary | ASM, C | Floppy | |
| PsychDOS | 4.6+ MB |
| DOS | 16-bit | Historic | Open-source | ASM | HD | |
| lEEt/OS | 0.5 MB |
| DOS | 32-bit | Modern | Open-source | ASM, C | Floppy | |
| BleskOS | 0.2 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| Blue Jay | 83 KB |
| Custom | 16-bit | Modern | Open-source | ASM | Floppy | |
| BoneOS | 3.0 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| BootChess | 4.0 KB |
| Custom | 16-bit | Modern | Open-source | ASM | Floppy | Chess in a bootsector |
| CatK | 3.2 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| Crazierl | 11 MB |
| Custom | 32-bit | Modern | Open-source | C, Erlang | Multiboot | An Erlang Operating System |
| Dusk OS | 0.4 MB |
| Custom | 32-bit | Modern | Open-source | C | HD | A 32-bit Forth |
| Floppy Bird | 6.5 KB |
| Custom | 16-bit | Modern | Open-source | C | Floppy | |
| HelenOS | 7.9 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | A microkernel-based multiserver OS |
| Hello v86 | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | |
| House | 1.1 MB |
| Custom | 32-bit | Modern | Open-source | Haskell | Floppy | |
| JX | 1.3 MB |
| Custom | 32-bit | Modern | Open-source | Java | Floppy | |
| KolibriOS | 1.3 MB |
| Custom | 32-bit | Modern | Open-source | ASM | Floppy | Various apps, games and demos |
| Little Kernel | 0.4 MB |
| Custom | 32-bit | Modern | Open-source | C | Multiboot | |
| M/CP | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | The Minimal Control Program |
| MikeOS | 0.2 MB |
| Custom | 16-bit | Modern | Open-source | ASM | CD | |
| Mobius | 1.3 MB |
| Custom | 32-bit | Modern | Open-source | C | Floppy | |
| Mu | 0.2 MB |
| Custom | 16-bit | Modern | Open-source | C | HD | |
| NanoShell | 3.5 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| NewOS | 0.6 MB |
| Custom | 32-bit | Modern | Open-source | C++ | Floppy | |
| Nope OS | 92 KB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| Oberon | 1.6 MB |
| Custom | 32-bit | Historic | Open-source | Oberon | HD | Native Oberon 2.3.6 |
| QNX 4.05 | 1.4 MB |
| Custom | 32-bit | Historic | Proprietary | C | Floppy | 1999 demo disk |
| SectorLISP | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | Bootstrapping LISP in a Boot Sector |
| Skift | 44 MB |
| Custom | 32-bit | Modern | Open-source | C++ | CD | A hobby OS built from scratch using C/C++ |
| Snowdrop | 0.4 MB |
| Custom | 16-bit | Modern | Open-source | ASM | Floppy | |
| Sol OS | 0.3 MB |
| Custom | 32-bit | Modern | Proprietary | ASM | Floppy | Simple graphical OS |
| Still Alive | 10 KB |
| Custom | 32-bit | Modern | Open-source | C | Floppy | |
| T3XFORTH | 59 KB |
| Custom | 16-bit | Historic | Open-source | ASM | Floppy | An old-school, plain vanilla FORTH system |
| TetrOS | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | Tetris that fits into the boot sector |
| ToaruOS | 6.3 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | |
| bootBASIC | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | A BASIC in 512 bytes of x86 machine code |
| Pillman | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | A yellow thing eats pills and is chased by monsters |
| bootLogo | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | Logo language in 508 bytes |
| bootRogue | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | a roguelike game that fits in a boot sector |
| dino | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | Chrome's t-rex based bootsector game |
| Sanos | 0.5 MB |
| Custom | 32-bit | Modern | Open-source | C | HD | |
| sectorforth | 512 B |
| Custom | 16-bit | Modern | Open-source | ASM | Bootsector | sectorforth is a 16-bit x86 Forth |
| Dancy | 1.3 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | Dancy Operating System |
| CuriOS | 6.6 MB |
| Custom | 32-bit | Modern | Open-source | C | HD | Simple GUI based OS inspired by AmigaOS |
| OS64 | 2.2 MB |
| Custom | 32-bit | Modern | Open-source | C | CD | Commodore 64 emulator OS for x86 (slow) |